


Soul of the Great Grail

by Abby_Ebon



Series: It's Not A Rabbit Hat [32]
Category: Fate/stay night & Related Fandoms, Harry Potter - J. K. Rowling
Genre: M/M
Language: English
Status: Completed
Published: 2012-06-27
Updated: 2012-06-27
Packaged: 2017-11-08 17:20:07
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,254
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/445608
Author URL: https://archiveofourown.org/users/Abby_Ebon/pseuds/Abby_Ebon
Summary: <blockquote class="userstuff">
              <p>Harry Potter is the vessel of the Great Grail.</p>
            </blockquote>





	Soul of the Great Grail

**Author's Note:**

> CkyKing: Harry Potter/Fate Zero or Harry Potter/Fate Stay Night
> 
> Harry is the vessel (or physical manifestation) of the Great Grail (not the Lesser Grail)  
> Pairing : Lancer(Diarmuid)/Harry (Fate Zero or Fate Stay Night)  
> Idea for Backstory :  
> The Potters are a branch that separated itself from the Einzbern Family, taking the name "Potter" to mock the homonculi created by the main family.  
> But they stole the creation process of the Greater Grail before leaving.  
> Then, they used it to create their vessel for the Great Grail as opposed to the creation of the vessel for the Lesser Grail by using Homonculi of the Einzbern.  
> Indeed, the first born (male or female) are always its vessel even though the link might stay inactive.
> 
> (This was another prompt where I'm introduced into a new fandom: first the Beowulf movie and now this anime. Unfortunately, I was only able to find and watch a few episodes of Fate Zero, enough to understand the prompt and play a little with the idea. The results, I think – are interesting….)

_To my son, Harry James Potter._

_I fear for your life, in what I have learned recently. If you read this, and I have not told this to you, I had reason to worry for my own life – an instinct that I did not heed. I am a witch, but not being born into this society as those of the old pure blood families are – I have found my way in it, and settled into it. Now I learn things too late that I would have turned away had I the chance and knowledge I do now._

_I would flee with you, but believe me, it would not help you – it would perhaps hurt you worse to grow up as I did, knowing nothing of magic and magi._

_The families you must be wary of – they do not call themselves wizards and witches, but mages or magi for magicians – the "pure blood" lines. Your father's father was not born named Potter, but Einzbern: the Potter name they took to mock that branch for forbidden and powerful dark magic – the magic art of making people, a process called homunculi. To hide in plain sight the most powerful magic known to the magi – that of granting a wish – for good or evil._

_The Einzbern did this to produce a vessel for the Great Grail. Yet never did they succeed in putting the Great Grail into a homunculi's body: the Great Grail is gone from the reach of the Einzbern. Your great-grandfather had taken it, and the name Potter, to hide the Great Grail in the bloodline of Potter heirs._

_The system as I understands it, chooses seven magi who summon seven legendary spirits, be they villains or heroes, it depends upon the magi: these "Servants" are called– Saber, Lancer, Archer, Rider, Castor, Assassin, and Berserker: the skills of the heroes of the past are often found in these 'ranks'._

_I do not know how their "Masters" are chosen by the Grail, perhaps not even the magi themselves know. The Grail knows._

_Oh, my Harry – I hope I am wrong, that I worry for nothing – but I believe there is a secret your father won't tell me, or that he doesn't know himself. I do not think he does, but I do – in his sleep he speaks with these "Servants" and sometimes if I lay quietly beside him, I hear them call him "Great Grail"._

_It runs in your blood, this Great Grail. I can do nothing but warn you of it, and wish you healthy from harm with all my love._

_Lily Evans- Potter_

Harry – eleven years old, and alone - said nothing in the empty Potter vault, his heart pounding in his ears, the paper in his hand – aged and yellowed – crinkling. His mother's handwriting, fluid and fleeting – full of fear and the fragility of feelings going unheeded: she'd written it, maybe in her last days – perhaps not, but it was his one warning, from beyond the grave – and he would heed it.

He knows less then his own mother about being a 'Great Grail' – but surely, there was a way to find out. A way to be sure: he has only to find a way. Harry closes his eyes, and thinks of his first year at Hogwarts, school of witchcraft and wizardry.

"It's too late, you know." Harry looked to see _him_ , one of the shadows that were always there in the corner of his eye, watching him. He'd thought them only blurs in his glasses. They had been there as Harry woke in the Hogwart's infirmary – and it had been clear to him, no one else saw the shadows – not even the ghosts. It had made him suspicious enough to go through what remained of his parents things safely locked in the _Gringotts_ Wizarding Bank vaults: he'd gotten here by bus and walking, from his Aunt's house: remembering the way when he'd gone with Hagrid. Or at least he'd thought he was safe here, in a locked vault only he possessed the key to – he'd asked it from Hagrid and received it to his own surprise with Dumbledore's approval. He had been wrong, of course he was wrong. It wasn't safe here.

"The Masters have been summoning Servants. The War begins anew." There is regret in him, this shadow-shape. He keeps his head low; his eyes adverted, as if he dares not look Harry in the face.

"Why?" Harry asks, and there is something like pleading in his voice. He does not want a War to start, does not want to be its source and focus because of the Great Grail lurking within him. It's not fair, it's in him, in his blood because he's a wizard – no, magi – and a Potter. The last Potter, the first born.

"It is the cycle, every sixty years..your father was preparing, he knew what was coming..." The shadow, it has a shape, and it's real – but it's not living. It's a spirit Harry realizes – one of _them_ : a Servant.

"Who are you?" The spirit looks up, meets his eyes – and smiles.

"Diarmuid Ua Duibhne – though my Master calls me simply Lancer." That's this Servant's class – and not a name, and Harry doesn't bother to say something so simple – because, clearly – the Servant knows that.

"Why come here to tell me this?" Harry holds himself, arms wrapped around his chest -not afraid to admit he's scared.

"You are a boy – and all the Servants will come to you, to swear to your protection. In secrecy from the Masters this is done, as the Potter bloodline demanded in order for the Holy Grail War to happen at all. To you I owe this gift, my greatest desire is half fulfilled, to serve a lord faithfully - and I owe you this thanks – my loyalty and honor I lay in a this vow – to protect you and serve you, Great Grail." Diarmuid kneels, head bowed low. Harry's face is flushed. He doesn't know what to do – thank him? Send him away. No – other Servants are coming, and he doesn't want to be alone when they get here.

They are coming, and no physical force – be it vault or not – will stop them. Or warn Harry of their coming.

"Will you stay?" Harry begs, quickly – because Diarmuid seems sincere. The Lancer looks up, frowning – but nods. It is not a long wait to see the next Servant – she steps from the shadows, head held high. In a dress of armor, like a knight striding forward to go to battle. She shines brighter then any treasures of the Potter vault.

"Great Grail…." Her eyes are on Lancer – but when Diarmuid's eyes widen and he shakes his head – she looks swiftly to Harry.

"A boy…" She murmurs, with shocked wide eyes – taking in the sight of him, and Harry feels his cheeks burning, imagining what she sees – an eleven year old boy she must swear to protect. Harry has to look at her, eventually, and does. Her eyes are kind and understanding, and it surprises him to see it. They are each not what the other expected.

"I am King Arturia Pendragon, Great Grail. I served thy Lady of the Lake with Excalibur and now as then I make the vow to raise my sword only for thy good and just world, and for thy world I will make War for my own and my Master's wish." King Arthur (a girl, but still _King Arthur_!) is kneeling on the floor of the Potter vault – and offers Excalibur, a gleaming sword with Fairy letters upon it, to Harry with bowed head and a fall of golden hair. It's a surreal feeling, and Harry doesn't know what to do – he looks to Diarmuid, who has drawn nearer to Harry, perhaps feeling his confusion.

"Keep it, and wield it as you will." Diarmuid speaks, when it is clear Harry will not. Arturia looks upon Diarmuid with narrowed eyes, but Harry – still speechless – nods with him in agreement.

"As the Great Grail wills…" Arturia muses softly, and with a final bow for Harry – fades.

"She is the Saber class, I would not doubt it." Diarmuid smiles into the shadows, something eager in his eyes.

"That's King Arthur…" Harry is awed, and intimidated, and sort of dismayed – he hadn't thought he would know of any of the heroic and legendary spirits. He doesn't doubt now that he will know of some of them, (for some may be better or worse then their reputation) and that in this War – he will see them die, again, and fade.

"Yes." Diarmuid ruffles Harry's hair, as if he is a brother, and he laughs. Harry smiles, a little, getting over his uneasy awe of King Arthur – but he has only to breath to feel another spirits presence pressing down upon him. Diarmuid's laughter changes, becomes ringing – challenging. He's felt the other spirit and can not help but call him out.

"Silence – for I am Gilgamesh, King of Kings." Everything about this spirit is golden, his hair, his armor, and his flashing eyes. It's the red cloak that marks him as royalty. Diarmuid's spine straightens, stiff and uneasy. Gilgamesh does not make the mistake of King Arthur; his golden eyes are settled upon Harry's green ones. He squats down, looking him over. He does not so much as glance to Diarmuid – and this is because, Harry is sure – Gilgamesh does not see him as any kind of threat or challenge to his person.

"There is much of my once companion Enkidu in you. I did not think to see that so in a boy - the Great Grail's embodiment on this earth. I will not serve you or any, but I will be your sworn friend. Death will not take you from my side while I War for a world of worthy beings to serve us. Will you take my friendship?" Gilgamesh offers his hand, and Harry hesitates for a moment – wondering at this King – but he certainly does not want to be his enemy. He takes the offered hand, and is startled when Gilgamesh kisses both sides of it. He doesn't have the chance to pull away in surprise, for Gilgamesh is gone – a spirit gone back into the shadows from which he came.

Diarmuid looks thoughtfully down at the hand Gilgamesh had taken and kissed. He is wary of that King's promise – and when Harry looks up, curious and with questions in his eyes.

"He is an Archer. This War will be one worthy of remembering, to the living and those of spirit like me." Diarmuid Ua Duibhne does not protest when Harry puts the hand that had been held and kissed by a King, into his own. He tucks Harry protectively against his side, for the next legendary spirits will not be nearly so kindly nor – he thinks - noble. All are heroes, but not all heroes have a personality that deserves the reverence history gives them.

The thunderous sound of a drawn chariot by bulls whose striking hooves echo in the vault eerily. This is a spirit of a hero who hides nothing of himself. He is red haired and wild looking, the hero who descends from his ancient divine chariot.

"And you are?" Diarmuid Ua Duibhne asks with raised brows, aware that Harry is tucked against him, heart beating as frantic and frightened as any boy ought to be.

"Iskandar, Alexander the Great, Al-Sikandar, The Lord of War, the Maharaorajah. The King of Conquerors." He waves a hand, as if these titles and names are nothing, and perhaps to him they are that. This is a man who knows what he desires, and he would die gladly to accomplish them.

"As long as you are, I will be – so I will protect you, Great Grail – but I want no wishes from you, for I will achieve my wishes by my own will or not at all - this world was once nearly mine, and I will conquer it – I will make it mine, and see what it fully offers – once and for all." He turns his back then, and nods to Harry – and takes his chariot and divine bulls back from where he came.

"The Rider class, swift – and I would teach him respect if you but asked it." Harry only shakes his head, he'd thought he'd learned something of Alexander the Great in history class, but this – this wasn't history, it was real. It was happening because of him, his blood.

"Likes of that one, does not know respect or quitting even upon being struck." At home in the shadows, this one is there – beside them, before either notice. It isn't until he speaks that they know.

"Hassan-i-Sabah, Great Grail – I mean not to harm you, if you can put The Hundred-Faced Hassan – back together again." Hassan-i-Sabah looks to the shadows surrounding them, the many bodies – and skills – and Harry realizes that these are multiple personalities, fragments – of one man: Hassan-i-Sabah.

Diarmuid Ua Duibhne takes a shaky breath, his eyes flashing. He does not know what he could do against this one – without a Master's mana – but if Harry is being threatened by the likes of a mere Assassin, Diarmuid will gladly see him dead.

"If it is your wish – and the wish of your Master – what can I do to stop you?" Harry only then takes a breath, wondering if it will be his last, and it is then that Hassan-i-Sabah snaps his fingers and all his many "faces" fall away into smoke and shadow, he bows.

"So be it, Great Grail." With his final words, he fades from sight. There is no knowing if he is truly gone or not. They both look to the shadows, and that is how Diarmuid spots the sword which gleams like light upon a lake's water. Sensing himself seen, a Black Knight steps forward.

"Berserker…" Diarmuid Ua Duibhne hisses, keeping himself between Harry and the Black Knight that has shown himself. He takes the helmet from his head, and his hair is a fall of darkness, his face pale and earnest.

"We are not so different, Lancer – for a women's love, we betrayed our most worthy lords. Behold, from the Great Grail's sight I do not hide – I am Lancelot of the Lake. With the light of Arondight, I defend thou Great Grail –even in darkness as my sanity deserts will remind me of this vow." Lancelot of the Lake does not bow, but he offers Arondight in the same way King Arthur had offered Excalibur – both are swords with Fairy marks and making.

Harry does not dare take it, or move to reject the vow – this Lancelot takes as acceptance. He turns his back to Harry and Diarmuid, to leave, but pauses. There is a sound like clapping.

"Oh so very noble, those lips, but that mind – it's twisted so with darkness, with pride and madness. I can taste your spirit's essence Lancelot of the Lake – and it is not so different from mine, either." This is a man who hunches in on himself, hiding it, appearing harmless. His grin is twisted and wicked.

"What do you want?" Harry's voice shakes, but he doesn't like this man – he's a wizard, a magi – just like Harry. The difference is he is older, and more powerful – and evil.

"From the Great Grail? Nothing: I have everything with a Master who understands me. For this, I thank you – and as thanks, I will kill you Great Grail, your bloodline has given hope to magi, a burning hope like flame for a wish – with your death that hope will be extinguished, ended with the Potter line. I know too of your enemy, Harry Potter – he I will help to kill you, but his hopes will be burning bright at your death – and it is then, know and hope, that I will kill him in your name." This is no hero, but he is legendary – in al the wrong ways. Like Voldemort his name lived on beyond his grave. That is how he manages to stand here, smiling and confident.

"Name yourself." Lancelot of the Lake demands, Arondight held aloft, standing between this powerful mad-man and the Great Grail.

"You dare? Corrupt Caster filth!" Diarmuid hisses at the Castor class Servant, reaching for his spear Gae Buidhe for the first time. No matter that this Castor is magi, Gae Buidhe would inflict wounds that would be unhealed, bleeding and weakening him until the spirit is defeated.

"I am but simple Gille de Rais, oh put your weapons away Berserker – you as well Lancer, I will not kill the Great Grail now – I'll let you live and hope another day will not end in your death – after all, a Servant can not serve their Master and the Great Grail at the same time, can they? And, oh – the trap of the Potter's was fine and made of their own vow – the Masters must not know the Great Grail…or not of us Servants would be summoned successfully." Mockingly, he bows, and the shadows move and reach for him, as if devouring him. Harry knows he did it himself, to make Harry worry. It had worked.

Lancelot looks to Harry, and then to the shadows that may very well represent his madness. They taint him, and the light of Arondight seems grim and grey.

"I will find his Master, Great Grail – you need not fear. I will kill them both." Harry is not comforted by that declaration – neither does he really believe it, but is glad to see Lancelot go.

"The sooner this War starts, the sooner it ends." Diarmuid does not say it will begin again – but Harry knows that without being told.

"You…you've got to go." Harry, in his own way, agrees. He doesn't like it, but he does know and realize it.

"You will be safe –from him - only when this War is ended." Diarmuid puts his forehead to Harry's cradling his hand in his hands, eyes pleading for an understanding.

"And I great a Master's wish..." Harry's lips curl downward, unhappily, but Diarmuid nods in agreement.

"What of my own wishes?" Harry asks, softly. Diarmuid is a Servant, tied to the Great Grail, summoned forth from it, brought to life by it. He knows Harry's wish, as all Servants do and feel – doing their best to answer the Great Grail's wish by the will of their Master magi. It is only that the Great Grail has so much within him – good and evil, and the power of potential, and the chosen Masters represent all the wishes within him – their Servants serve the Great Grail's will.

Harry has seen the Servants and knows now what is within his own soul; the soul of the Great Grail is corrupted by another – or else Gille de Rais would never have been summoned out of darkness and shadows of spirits. Diarmuid thinks – knows – it is by the one whom Gille de Rais spoke of, the enemy – and somehow, the Servants loyal to the Great Grail must fight two Wars at once.

"Wish to be whole and happy and I will see this granted to you." Diarmuid kisses the boy's forehead, knowing that if the Great Grail were older, or a women, Diarmuid Ua Duibhne would love him and be loved. It is a bitter sweet thing, to know a true lord worthy of love and loyalty, but to serve a Master to whom these things are nothing.

**Author's Note:**

> 4th Holy Grail War:
> 
> (Class : Servant – Master)
> 
> Saber: Arturia Pendragon - Emiya Kiritsugu (husband of Irisviel von Einzbern, homunculus and physical embodiment of the Lesser Grail of the Einzbern family.)
> 
> Lancer: Diarmuid Ua Duibhne - Kayneth Archibald El-Melloi
> 
> Archer: Gilgamesh -Tohsaka Tokiomi/Kotomine Kirei
> 
> Caster: Gille de Rais "Bluebeard" - Uryuu Ryuunosuke
> 
> Rider: Alexander the Great - Waver Velvet
> 
> Berserker: Lancelot of the Lake - Matou Kariya
> 
> Assassin: The Hundred-Faced Hassan - Kotomine Kirei
> 
> \----
> 
> sequel : [Heart of the Great Grail ](http://archiveofourown.org/works/562952)

**Works inspired by this one:**

  * [Heart of the Great Grail](https://archiveofourown.org/works/562952) by [Abby_Ebon](https://archiveofourown.org/users/Abby_Ebon/pseuds/Abby_Ebon)




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